Everything I have read and researched is to go with the 2" stuff. Particularly for any reclining setup. The 2" will work better with a Hans setup. they say that the 2" stuff is better for antisubmarining from a front end crash(think about what happens when you get thrown into the front, on a crash!!). Read the schroth literature. I have 3" on my shoulder setup and I can tell you, you will get chaffed around the neck.
Bill